Answer:
15 bundles of roofing shingles
Explanation:
Total bundles of roofing shingles = 29
He carries two bundles at a time
How many bundles are still on the ground after his seventh trip up the ladder?
First trip = 2 bundles of roofing shingles
Second trip = 2 bundles of roofing shingles
Third trip = 2 bundles of roofing shingles
Fourth trip = 2 bundles of roofing shingles
Fifth trip = 2 bundles of roofing shingles
Sixth trip = 2 bundles of roofing shingles
Seventh trip = 2 bundles of roofing shingles
Total bundles of roofing shingles carried in 7 trips = 2 + 2 + 2 + 2 + 2 + 2 + 2
= 14 bundles of roofing shingles
Bundles still on ground after 7 trips = Total bundles of roofing shingles - Total bundles of roofing shingles carried in 7 trips
= 29 - 14
= 15 bundles of roofing shingles